One problem with playground swings is that children often throw the swings over the upper crossbar of the swing set so that the swings may ultimately become wrapped around the crossbar. Wrapped swings are typically unusable and must be unwrapped by maintenance personnel. Even when the swing is evenly wrapped around a crossbar such that it appears to be useable, use of a wrapped swing may damage the crossbar or the chains that support the swing seat, or could prove dangerous to the user. Unwrapping swings consumes the time of maintenance personnel and is thus expensive. It is thus desirable to provide a device that prevents the swings from being wrapped over the crossbar.
One device known in the art for preventing swing wrapping is disclosed in U.S. Pat. No. 5,147,247. This patent discloses a barrier assembly for swings that is mounted on top of the crossbar of the swing set. The barrier is configured to prevent a swing from passing over the crossbar and becoming wrapped. Although functional, this device requires a considerable amount of material and must be configured differently for different sized swing sets.
Another device known in the art for preventing swing wrapping includes a pair of clevises that are each supported from a clevis housing. The clevis housings are spaced by an outer bar that slides over the upper crossbar of a swing set. Each clevis housing rotates on a set of ball bearings such that the devises and the outer bar rotate together as a unit. Although this device is useful for preventing swing wrapping, it is rather expensive to manufacture due to the ball bearings and the machining required to create the individual parts. Furthermore, the distance between the clevises cannot be easily adjusted because the distance is permanently set by the outer bar. The device is also relatively heavy.
When designing outdoor playground equipment, numerous safety standards must be met before the equipment may be installed and used on a playground. One of these standards limits the size and type of protrusions that may be present on the equipment. A protrusion is generally something that extends outwardly from the equipment and presents an area where loose articles of clothing or other items may be snagged. One common device that creates a protrusion is a nut and bolt combination. A bolt necessarily must protrude through a surface so that a nut may be screwed onto the threaded end of a bolt. However, the protruding nut and bolt end create a safety hazard in the nature of a protrusion. Thus, it is desirable that any device that is used to prevent swing wrapping accomplish its purpose without creating protrusions as defined by the ASTM's Standards for Playground Equipment.